In a barratrous manner; in a way that involves fraud, deception, or criminal conduct at sea.
From barratrous plus -ly suffix forming an adverb. A rare adverbial form describing actions done with fraudulent intent in maritime contexts.
This adverb is essentially theoretical—you're unlikely to find 'barratrously' used in actual legal documents because by the time the adverb form would make sense, the word itself had become archaic!
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